LASIK or Lasik ( laser –assisted in situ Keratomileusis ) is a type of refractive surgery for correcting myopia, hyperopia, and astigmatism. LASIK is performed by ophthalmologists using a laser. The procedure is generally preferred to photorefractive keratectomy, PRK, (also called ASA, Advanced Surface Ablation) because it requires less time for the patient's recovery, and the patient feels less pain overall. However, there are instances where a PRK/ASA procedure is medically justified as being a better alternative to LASIK.
Procedure :
A suction ring is placed on the eye to secure the eye and maintain pressure within the eye while the corneal flap is created. A microkeratome, an automated microsurgical instrument similar in design to a carpenter's plane, is used to create a thin corneal flap which remains hinged beneath the upper eyelid.The corneal flap is 160 to 180 microns thick, about 30% the corneal thickness which is typically about 550 microns. Patients do not feel or see the cutting of the corneal flap, which takes only a few seconds. Corneal "flap making" has been researched and developed for 40 years, providing us with a long history of safety and stability.
The corneal flap is then laid back and the inner stromal layers of the cornea lasered with the patient's prescription. An ultraviolet light from the excimer laser reshapes the internal cornea with an accuracy of 1/2000th of a milimetre. For reshaping the cornea, the corneal surface is polished with the help of a pre-programmed excimer laser. This changes the refractive power of the cornea thus eliminating the refractive error of the eye.
The corneal flap is then repositioned and the flap and interface rinsed. Once the procedure is completed, the surgeon will wait 2 to 3 minutes to ensure the corneal flap has fully re-adhered. At this point, patients can blink normally and the corneal flap remains secured in position by the natural adherence within the cornea. While it is possible to dislodge the corneal flap during the first day or two by physically rubbing the eye, this event is actually quite rare. After the first week, LASIK patients can resume their full exercise activities.
Postoperative care:
Patients are usually given a course of antibiotic and anti-inflammatory eye drops. These are continued in the weeks following surgery. Patients are usually told to sleep much more and are also given a darkened pair of shields to protect their eyes from bright lights and protective goggles to prevent rubbing of the eyes when asleep and to reduce dry eyes. They also are required to moisturize the eyes with preservative-free tears and follow directions for prescription drops. Patients should be adequately informed by their surgeons of the importance of proper post-operative care to minimize the risk of complications.
